condition mean min max ZT0-3 3.701695 3.31248 4.18591 ZT4-7 3.437595 3.437595 3.437595 ZT8-11 4.036975 4.036975 4.036975 ZT12-15 5.932779999999999 5.302474999999999 6.563085 ZT16-19 5.01145 5.01145 5.01145 ZT20-23 4.89683 4.89683 4.89683